[plt-scheme] Serializing/deserializing in a servlet

I believe that they wouldn't be interfered with by the separate
namespaces. But if the "real" structs Eddie wants have properties,
then IIRC, prefab'd structs can't have them.

Jay

On Fri, Nov 28, 2008 at 10:26 PM, Robby Findler <robby at cs.uchicago.edu> wrote:
> Would a #:prefab struct help?
>
> Robby
>
> On Fri, Nov 28, 2008 at 11:23 PM, Jay McCarthy <jay.mccarthy at gmail.com> wrote:
>> Servlets don't share namespaces, in particular, this means that
>> servlets can't interact with each other through structs, which are
>> generative. You can solve this by passing the #:make-servlet-namespace
>> argument to serve/servlet passing in the module spec of the source of
>> the struct. I could debug this program tomorrow, but I don't have time
>> right now.
>>
>> Jay
>>
>> On Fri, Nov 28, 2008 at 12:45 PM, Eddie Sullivan <eddieSull at hotmail.com> wrote:
>>> Hi.
>>> The following simple code works well normally, but when run in a servlet
>>> causes a strange error:
>>>
>>> #lang scheme
>>>
>>> (require scheme/serialize
>>>        web-server/servlet-env)
>>>
>>> (define-serializable-struct test-struct
>>>  (a))
>>>
>>> (define (test-serialize)
>>>  (let* ([s (make-test-struct
>>>           "Eddie Sullivan")]
>>>        [serialized-s (serialize s)]
>>>        [new-s (deserialize serialized-s)])
>>>   (display (format "test-serialize: Saved a: ~a" (test-struct-a
>>>                                                   new-s)))))
>>>
>>>
>>> (define (go)
>>>  (serve/servlet start))
>>>
>>> (define (start request)
>>>  (test-serialize))
>>>
>>>
>>> In DrScheme (Windows, vs 4.1.3), if I call (test-serialize), I see the
>>> expected result:
>>>
>>> test-serialize: Saved a: Eddie Sullivan
>>>
>>> On the other hand, if I call (go), I see the following error:
>>>
>>> Servlet (@ /servlets/standalone.ss) exception:
>>> test-struct-a: expects args of type <struct:test-struct>; given instance of
>>> a different <struct:test-struct>
>>>
>>> Any tips?
>>> Thanks.
>>> -Eddie Sullivan
>>>
>>>
>>>
>>> _________________________________________________
>>>  For list-related administrative tasks:
>>>  http://list.cs.brown.edu/mailman/listinfo/plt-scheme
>>>
>>
>>
>>
>> --
>> Jay McCarthy <jay at cs.byu.edu>
>> Assistant Professor / Brigham Young University
>> http://jay.teammccarthy.org
>>
>> "The glory of God is Intelligence" - D&C 93
>> _________________________________________________
>>  For list-related administrative tasks:
>>  http://list.cs.brown.edu/mailman/listinfo/plt-scheme
>>
>>
>



-- 
Jay McCarthy <jay at cs.byu.edu>
Assistant Professor / Brigham Young University
http://jay.teammccarthy.org

"The glory of God is Intelligence" - D&C 93